Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-07-03
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
7 pages, 3 figures, accepted in Astronomy and Astrophysics
Scientific paper
The H.E.S.S. (High Energy Stereoscopic System) telescopes observed Coma for ~8hr in a search for gamma-ray emission at energies >1TeV. The large 3.5deg FWHM field of view of H.E.S.S. is ideal for viewing a range of targets at various sizes including the Coma cluster core, the radio-relic (1253+275) and merger/infall (NGC 4839) regions to the southwest, and features greater than deg away. No evidence for point-like nor extended TeV gamma-ray emission was found and upper limits to the TeV flux F(E) for E>1, >5, and >10TeV were set for the Coma core and other regions. Converting these limits to an energy flux E^2F(E) the lowest or most constraining is the E>5TeV upper limit for the Coma core (0.2deg radius) at ~8Crab flux units or ~10^{-13}ph cm^{-2} s^{-1}. The upper limits for the Coma core were compared with a prediction for the gamma-ray emission from proton--proton interactions, the level of which ultimately scales with the mass of the Coma cluster. A direct constraint using our most stringent limit for E>5 TeV, on the total energy content in non-thermal protons with injection energy spectrum proportional to E^{-2.1} and spatial distribution following the thermal gas in the cluster, is found to be ~0.2 times the thermal energy, or ~10^{62}erg. The E>5 TeV gamma-ray threshold in this case corresponds to cosmic-ray proton energies >50TeV. Our upper limits rule out the most optimistic theoretical models for gamma ray emission from clusters and complement radio observations which constrain the cosmic ray content in clusters at significantly lower proton energies, subject to assumptions on the magnetic field strength.
Aharonian Felix A.
The HESS Collaboration
No associations
LandOfFree
Constraints on the multi-TeV particle population in the Coma Galaxy Cluster with H.E.S.S. observations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Constraints on the multi-TeV particle population in the Coma Galaxy Cluster with H.E.S.S. observations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constraints on the multi-TeV particle population in the Coma Galaxy Cluster with H.E.S.S. observations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-529759